The present invention relates to a magnetic recording method which may be used with an R-DAT (rotary digital audio tape recorder) or the like.
Two types of data are recorded with an R-DAT, PCM audio data and sub-code data. Sub-code data is recorded in two regions, SUB-1 and SUB-2, of a track. The sub-code data in each region is composed of eight-block data, with one block being composed of 32-symbol data (one symbol consisting of 8 bits). Each block is labelled with hexadecimal addresses (composed of the ten numerals 0 to 9 and the six alphabetic characters A to F).
A set of odd-numbered symbols and a set of even-numbered symbols taken from two blocks, one labelled with an even-numbered address and the other labelled with an address of an odd number greater than that of the even-numbered address, are treated with as a single unit for error correction. If the set of odd-numbered symbols is referred to as error correction block A and the set of even-numbered symbols as error correction block B, it then follows that two error correction blocks A and B exist in the above-defined two blocks. Each error correction block consists of 32 symbols, 28 of which are assigned to data and the remaining four to parity.
In the sub-code data region, program time, absolute time, TOC information and other such types of information can be recorded as a packet. No sub-code is updated in a frame composed of two consecutive tracks with different head azimuths. An example of the information to be recorded in the two tracks is a time code for the same point in time. Each packet consists of a four-bit item and 60-bit data and parity. An item signifies the content of data of interest. For instance, items (0001) and (0010) represent a program time and an absolute time, respectively. Item (0000) denotes null information, with all data bits in it being zero.
In a conventional magnetic recording method, a situation occurs where a first unit in the apparatus reproduces a signal that is recorded with a second unit. Even if the sub-code data received as a signal to be recorded with the second unit contains an uncorrectable error, the conventional apparatus records the data unchanged. This potentially causes the apparatus to operate erroneously when the erroneous data is reproduced.